A glass that bends but doesn't break
Afraid of keeping glass-made decorative pieces at home as your naughty kids won't spare them for long? Not any more.
Here comes a glass that bends but does not break when dropped - thus offering improved man-made designs in the future.
Engineers at McGill University in Canada have developed a technique that makes the glass simply bend and become slightly deformed when dropped.
The inspiration comes from the mechanics of natural structures like seashells in order to significantly increase the toughness of glass.
"Mollusk shells are made up of about 95 per cent chalk which is very brittle in its pure form," says professor François Barthelat from McGill's department of mechanical engineering.
But nacre - or mother-of-pearl - which coats the inner shells is made up of microscopic tablets that are a bit like miniature Lego building blocks and known to be extremely strong and tough.
"Imagine trying to build a Lego wall with microscopic building blocks. It's not the easiest thing in the world," explained Barthelat.
Instead, the researchers studied the internal 'weak' boundaries or edges to be found in natural materials like nacre.
They used lasers to engrave networks of 3D micro-cracks in glass slides in order to create similar weak boundaries.
The results were dramatic.
The researchers were able to increase the toughness of glass slides 200 times compared to non-engraved slides.
By engraving networks of micro-cracks, they were able to stop the cracks from propagating and becoming larger.
According to Barthelat, the process would be easy to scale up to any size of glass sheet since people are already engraving logos and patterns on glass panels.
"What we know now is that we can toughen glass, or other materials, by using patterns of micro-cracks to guide larger cracks, and in the process absorb the energy from an impact," said Barthelat.
The reseachers now plan to go on to work with ceramics and polymers in future, said the study published in Nature Communications.
